Nothing can explain how I felt the moment the hammer went down to mark the decision yesterday - Tasmania's Wilderness World Heritage Area was officially extended by 170,000 hectares. Forests that I had spent the past six years of my life fighting to defend, some of the most contentious forests that thousands of people here and around the world have fought to save for over two decades, were now officially listed.

There's one patch of that forest that I know like the back of my hand. It's the Tyenna Valley, surrounding a 400 year old giant Eucalypt known to me as the Observer Tree, and whose upper canopy I lived in for over 14 months without once setting my feet on the ground.

When I climbed that tree in mid-December 2011, I had no idea what I was really getting myself in for. But I vowed to remain until the forests were protected. I didn't know if that day would be two or 10 years away, but I had hoped for the sake of the forests that it wouldn’t take that long. The experience of living on a small platform 60 meters above the ground for over a year was one I will never forget: from the powerful moments of inspiration, to the depths of loneliness and isolation. But if I learnt one thing it was how much one action can make a difference.

From my tree top platform, armed with solar panel and computer, I shared that forest with the world; blogging and speaking via video link up to conferences, school groups and festivals. I was able to expose the reality of forest destruction in Tasmania, particularly important for those international customers purchasing wood products from here, many of which have been misleading labelled as “eco” products despite being sourced from high conservation value forests.

'From my tree top platform, armed with solar panel and computer, I shared that forest with the world'. Photograph: Miranda Gibson

The gathering global momentum behind the campaign, plus pressure from the World Heritage Committee themselves and also the political influence of Federal Greens members, all helped to put pressure on the Australian government who eventually made a nomination for World Heritage in February.

Although a bushfire burning within 1.5km from my tree eventually forced me to evacuate in March this year, my heart had not really left the tree tops. Every day in my mind I was still watching over that forest, just as I had done for the 449 days atop the tree. Every day a thought hung over me like a cloud – the knowledge that the loggers might return and begin clearfelling once more. Today, as the shock wears off, the reality starts to sink in, and that dark cloud of uncertainty lifts. The Observer Tree and the forest surrounding it are now officially protected.

Like the Observer Tree, there's another part of Tasmania's wild forests that is close to my heart – the Upper Florentine Valley, where I spent many years on the front lines of the forest debate, alongside countless others. Often cold, wet and muddy, we put our bodies on the line to hold off the logging of an intact valley of old growth forest that was surrounded on three sides by World Heritage, but was under imminent threat. We faced sometimes harsh conditions, the camp being attacked and even fire bombed on one occasion. A protestor and I were also assaulted by a group of loggers, one wielding a sledgehammer. But none of this deterred us from our mission: to bring an end to the industrial scale destruction of Tasmania’s irreplaceable ecosystems. Today I know how much it was all so incredibly worth it.

Of course, success is bittersweet in the fight for environmental protection. Because with almost every win, there is another battle waiting around the corner that needs to be fought. The World Heritage extension is just one step towards achieving much needed conservation outcomes in Tasmania. There are hundreds of thousands of verified high conservation value forests that have not been protected through this process. The recently signed Tasmanian Forest Agreement does little to protect native forests, and in fact props up an otherwise economically unviable industry, endorsing corrupt companies and entrenching outdated practices like clearfelling and high intensity burns.

But just for today, I will put those thoughts aside and enjoy the success of how far we have come. In the Upper Florentine there were plans to log 15 coupes (areas of logging) within a three year period. Due to the blockade, Forestry Tasmania only managed to fell two and half of those. Out of 10.5 km of proposed roading into the pristine forests, only 2km were ever built. Thousands of people from all walks of life took part in actions to ensure those giant trees remained standing.

As a community, we have a lot to be proud of today – knowing the part we have played in protecting these ancient forests and the animals that rely on them for survival, for now and for future generations.